Can't delete anything from desktop as limited privilege user

The other day I removed the account that I usually use for my day to
day activity from the Administrator group, and made it just part of
the plain User group. I did this to further secure my computer, and
just use the admin account when higher privileges are needed. Now,
however, it seems that the entire contents of the C drive is off
limits to this limited account ("access is denied"). I can create
files on the desktop, but if I try to delete what I just created, I
get "C:\ is not accessible. Access is denied". I can't browse any of C:
\ drive either, getting the same message. I can still run all my
programs on C. Any thoughts on what is up?

Thanks,
Marcus